The aim is to draw up a blueprint on how tunnel policing should operate.

After the inquest on 14-year-olds Darren Franey and Scott Veach, from Kensington, Liverpool, coroner Andre Rebello expressed concern that the tunnel police do not constitute a police force "in the accepted sense."

Mr Benn said he shared Mr Rebello's concerns that policing should be "safe and effective."

Wirral South MP Ben Chapman said: "I welcome this latest development.

"I have serious concerns regarding the accountability and role of non-territorial police forces."

Mr Chapman, who campaigned against Merseytravel's plan to uprate tunnel charges annually, went on: "In particular, I wonder whether it is necessary to have a separate police force to facilitate safe traffic flow management in the two tunnels.

"Why are roads in tunnels different in this respect to other roads and highways?"

He said both the Home Office and department of transport officials will be involved in the inquiry, along with other organisations.

Merseytravel has previously signalled that it will cooperate fully with such a probe.